Cadmium zinc telluride (CdZnTe) semiconductor crystals have been shown to be the most promising materials for x-ray and γ-ray detection [1, 2]. However, the yield of high quality crystal is still limited by some important problems. Several researchers have shown a possibility to improve crystal quality by CO2 laser irradiation [3, 4]. This method has disadvantages, such as long processing time, about 100 h, and damage of crystal surface. The improvement of the quality of CdZnTe crystal was observed after irradiation by Nd:YAG laser with 3.6×104 pulses. The leakage current of CdZnTe detector decreases by 40%. The enhancement of energy resolution of CdZnTe detector, especially at low energies, takes place after irradiation by the laser. This effect is explained by small defect precipitation on to Telluride (Te) inclusion due to thermogradient effect around it. II. EXPERIMENTS AND DISCUSSION In this research CdZnTe crystal is grown by vertical gradient freezing method using the high-purity Cd, Zn and Te: 7N materials and doping with 3 ppm of Indium characterized by high concentration of non-controllable impurities and Te inclusion is used. Shallow impurities have strong influence on electrical conductivity of semiconductor and leakage current of radiation detector. Infrared transmission microscopy was used to characterize CdZnTe samples, particularly concentration of Te inclusions. Single crystals Cd1-xZnxTe have been irradiated by the Nd:YAG laser with the following parameters: wavelength λ = 1064 nm, pulse duration =3 ns, intensity 6.6 MW/cm2. Treatment by laser was carried out at room temperature and atmospheric pressure. CdZnTe samples were irradiated Nd:YAG laser and afterwards current voltage (I-V) characteristic measurements were performed. I-V characteristic measurements showed that sample resistivity is rising after irradiation by 3.6×104 laser pulses and the dark current is decreasing by 40%.After reaching specific number of pulses, saturation effect can be observed. It means that no more changes of CdZnTe sample resistivity were observed. FTIR spectra of CdZnTe showed that after irradiation by the laser transparency of the crystal is increased (Fig.1). To characterize sample as radiation detector γ-ray spectroscopy measurement was used. Measurements of γ-ray spectroscopy of CdZnTe crystal irradiated by the laser have shown the improvement of the energy spectral resolution (Fig.2). It can be concluded the quality of CdZnTe crystal is improved. III. CONCLUSIONS 1. The possibility to increase of Cd0.9Zn0.1Te crystal quality after irradiation by Nd:YAG laser was shown. 2. Improvement of CdZnTe crystal quality is explained by segregation of defects on to Te inclusion due to gradient of temperature around it. IV. REFERENCES [1] T.E. Schlesinger, et all. Cadmium zinc telluride and its use as a nuclear radiation detector material. Materials Science and Engineering: R: Reports, 32(4/5) (2001), pp.103-189. [2] F. Lebrun. Semiconductor detectors for soft gamma-ray astrophysics. Nuclear Instruments & Methods in Physics Research Section, 563(1) (2006), pp.200-204. [3] M. Meier, M.J. Harrison, S. Spalsbury, D.S. McGregor. Laser-induced thermomigration of Te precipitates in CdZnTe crystals. Journal of Growth. 311(2009), pp.4247-4250. [4] S.V. Plyatsko, L.V. Rashkovetskyi. Laser-stimulated compensation of volume defects in p-CdZnTe. Semiconductors, 40, (2006), pp.287-295.